Fluid having improved lubricity properties

1. A lubricant, comprising:

5.0 wt. % of an ester oil;

a hydrocarbon oil selected from the group consisting of a mineral oil of Group I, II and III;

and

12.78 to 14.2 wt % of a polyalkyl(meth)acrylate copolymer having a weight average molecular weight of from 25,000 to 160,000,

the copolymer comprising, in copolymerized form,

a) 13 to 25 wt % based on a total weight of the polyalkyl(meth)acrylate copolymer of units of one or more alkyl(meth)acrylate monomers of formula (I):

wherein

R is hydrogen or methyl, and

R 1 is a linear, branched or cyclic alkyl residue with 1 to 4 carbon atoms;

b) 36 to 87 wt % based on a total weight of the polyalkyl(meth)acrylate copolymer of units of one or more alkyl(meth)acrylate monomers of formula (II):

wherein

R is hydrogen or methyl, and

R 2 is a linear, branched or cyclic alkyl residue with 5 to 15 carbon atoms; and

c) 0 to 39 wt % based on a total weight of the polyalkyl(meth)acrylate copolymer of units of one or more alkyl(meth)acrylate monomers of formula (III):

wherein

R is hydrogen or methyl,

R 3 is a linear, branched or cyclic alkyl residue with 16 to 400 carbon atoms; and

d) units of comonomers.

2. The lubricant of claim 1 , wherein a weight ratio of the polyalkyl(meth)acrylate copolymer to the ester oil is in a range of 2.5:1 to 2.8:1.

3. The lubricant of claim 1 , wherein the ester oil is selected from the group consisting of a dicarboxylic acid ester and mixtures thereof.

4. The lubricant of claim 1 , wherein the ester oil is selected from the group consisting of a di-alkyl-adipate and mixtures thereof.

5. The lubricant of claim 1 , wherein the ester oil is selected from the group consisting of a dialkyl substituted sebacate and mixtures thereof.

6. The lubricant of claim 1 , wherein the polyalkyl(meth)acrylate copolymer is obtained in the presence of at least one of the ester oil and the hydrocarbon oil.

7. The lubricant of claim 1 , wherein the polyalkyl(meth)acrylate copolymer is obtained in the presence of the ester oil.

8. The lubricant of claim 1 , wherein the ester oil is a dialkyl dicarboxylate, an alkyl(meth)acrylate, or a mixture thereof.

9. The lubricant of claim 8 , wherein the ester oil is a dialkyl dicarboxylate and the dialkyl dicarboxylate is at least one selected from the group consisting of a dialkyl adipate, a dialkyl pimelate, a dialkyl suberate, a dialkyl azelate, a dialkyl sebacate, and mixtures thereof.

10. The lubricant of claim 1 , wherein the polyalkyl(meth)acrylate copolymer has a polydispersity in the range of 1.05 to 2.0.

11. A method for preparing a lubricant, the method comprising:

polymerizing a monomer mixture in the presence of at least one of an ester oil and a hydrocarbon oil; the monomer mixture comprising,

a) 13 to 25 wt % of one or more alkyl(meth)acrylate monomers of formula (I):

wherein

R is hydrogen or methyl, and

R 1 is a linear, branched or cyclic alkyl residue with 1 to 4 carbon atoms;

b) 36 to 87 wt % of one or more alkyl(meth)acrylate monomers of formula (II):

wherein

R is hydrogen or methyl, and

R 2 is a linear, branched or cyclic alkyl residue with 5 to 15 carbon atoms; and

c) 0 to 39 wt % of one or more alkyl(meth)acrylate monomers of formula (III):

wherein

R is hydrogen or methyl,

R 3 is a linear, branched or cyclic alkyl residue with 16 to 400 carbon atoms; and

d) units of comonomers;

wherein

a weight average molecular weight of the polyalkyl(meth)acrylate copolymer is from 25,000 to 160,000, and

the hydrocarbon oil is selected from the group consisting of a mineral oil of Group I, II and III.